[166] What was
learned with the Suntan project? The technology of liquid hydrogen
was advanced in several ways. There is concurrently a revival of
interest in hydrogen-fueled aircraft. As before, however, their
potential value is controversial. NASA held a special conference on
hydrogen-fueled aircraft in 1973 and has sponsored industry design
studies of both subsonic and supersonic configurations. Although no
specific development has started, NASA continues to sponsor research
applicable to hydrogen-fueled aircraft.

On the other hand, Kelly Johnson, who turned
back to petroleum fuels and designed the highly successful SR-71,
remains disenchanted with liquid hydrogen. In 1974, he summed up his
view: "Today, there is regenerated interest in liquid hydrogen for
aircraft propulsion, but considering all phases of the problem, I do
not think we will have such aircraft in the foreseeable
future."54 Seaberg, who managed design study contracts with
Boeing, Convair, and North American Aviation as part of the Suntan
effort in 1957, agrees with Johnson's 1974
assessment.55 The essence of technological progress, however, is the
conversion of the impossible to the possible, so the case for
hydrogen-fueled aircraft remains open.

Although Suntan technology and equipment have
yet to find application in aircraft, they soon found application in
rocket propulsion. In 1958, the Suntan management team began
searching for ways to use the technology their project had generated,
as well as equipment like the boost pump and the hydrogen
liquefaction plants. One result was a proposal to use liquid hydrogen
in a rocket engine for the rapidly developing space program. Like a
phoenix rising from the ashes, the technology and equipment of Suntan
would indeed play a major role in the space program of the 1960s. To
learn how this occurred, we must next consider several other
developments that were running concurrently with Suntan-activities at
Pratt & Whitney, General Dynamics, North American Aviation, NACA,
and the Department of Defense.

[167] Fig. 47. Suntan
management team: Col. Norman C. Appold. top left; Lt. Col. John D.
Seaberg, top right; Maj. Alfred J. Gardner, bottom left and Capt. Jay
R. Brill. All engineers, Appold and Gardner each held two masters
degrees, Brill one. Appold and Gardner were combat pilots and Seaberg
a base executive during WW II. Brill graduated from West Point 3
years after the war. Appold headed the engine laboratory at Wright
Field for 5 years prior to becoming the Suntan project manager. After
Suntan, Seaherg managed the Centaur development for both the Air
Force and NASA, assisted by Gardner and Brill. All except Brill
retired as colonels: Appold heads the C-5 project for
Lockheed-Georgia; Seabergmanages remotely-piloted-vehicle
R&D at Wright Field; and Gardner is an assistant to the president
of Lockheed Missiles and Space Co. Brill became a brigadier general
in 1975 and manages the A-10 development at Wright
Field.